Such an axial piston machine can be used as axial piston pump or axial piston motor. The swash plate is angled with respect to the axis of rotation. When the axial piston machine is used as motor, the cylinder is supplied with hydraulic fluid under pressure pressing the piston out of the cylinder. The slipper which contacts the swash plate generates a grade resistance driving the cylinder drum in rotation about the axis of rotation. When the axial piston machine is used as pump the cylinder drum is driven in a rotational movement from the outside. The slipper of the piston together with the contact at the swash plate forces the piston to move back and forth within the cylinder thereby pressurizing the hydraulic fluid.
The slipper is pressed against the swash plate by the pressure within the cylinder and by means of a retaining mechanism. In order to avoid too much wear in the swash plate and the slipper a pressure area is provided on the slipper which is pressurized as well, in many cases by the pressure of the hydraulic fluid within the cylinder. The size of the pressure area multiplied with the pressure in the pressure area creates a force which should balance out the force generated by the pressure within the cylinder and acting on the piston. The total pressure area is a combination of a high pressure area and a seal area. The pressure in the seal area decreases from the radially inner side to the radially outer side and is in average therefore lower than the pressure in the high pressure area. Furthermore, the slipper is tilted. This makes it necessary to define the pressure area to be larger than the inner diameter of the cylinder. This requires a certain space to accommodate the desired number of cylinders in the cylinder drum.